单电源供电的多档位高精度恒流源电路

A High Precision Constant Current Source Circuit with a Single Power Supply

针对现有的恒流源要正负双电源供电精度不很高等方面的不足,设计了款单电源供电的多档位高精度恒流源电路。该恒流源电路选用增益高、转换速度快可由单电源供电的集成运放LM358和功率场效应管构成压控恒流源,因此可由单电源供电工作;采样部分采用精度千分之一以上的电阻,档位选择开关选用接触电阻小于5mΩ的双路开关,双路开关并联当一个开关使用进一步减小接触电阻,给定电压部分精度高。样品实验结果表明,该恒流源精度很高,使用方便。

In view of the shortcomings of the existing constant current source,the precision of both positive and negative power supply is not very high.A high precision constant current source circuit for a single power supply with a single power supply is designed.The constant current source circuit with high gain and fast switching speed by single power supply integrated operational amplifier LM358 and power FET constitute a voltage controlled constant current source,it can be managed by a single power supply;sampling part adopts resistance accuracy of more than 1/1000,the gear selection switch with double road contact resistance is less than 5mΩ.Switches,dual parallel switch when a switch is used to further reduce the contact resistance,a given voltage high precision part.The experimental results show that the precision of the constant current source is very high and it is easy to use.